1. Field of the Invention
The present invention generally relates to a technology of resource allocation in small-cell networks, in particular, to a resource allocation server and a communication system in small-cell networks.
2. Description of Related Art
The explosive growth of mobile broadband wireless services have driven and expedited the deployment of the Third Generation Partnership Project (3GPP) LTE (Long Term Evolution) networks. The global mobile broadband subscriptions and the global mobile data traffic have been growing exponentially in the last few years. To support the exponentially growing mobile data traffic, not only is the wireless bandwidth a major concern, the power consumption is also becoming a challenging issue. Statistics show that, the total power consumption to support an operator's hundreds of millions of subscribers is over ten billion kilowatt hours, wherein about 70 percent of the power is used by the base stations (BSs).
To meet the bandwidth demands with an environmental friendly transmission technology, an emerging idea is to deploy large numbers of low-power and low cost femtocell BSs or access points (APs) in metropolitan areas, and coordinate the transmissions of the tens of thousands of BSs/APs using a cloud-based radio access network (C-RAN). Unlike typical RANs where the baseband units (BBUs) and the radio function units are situated together, the C-RAN separates the radio function units (also referred to as the remote radio heads (RRHs)) from the BBUs, wherein the RRHs are deployed with antennas at the remote site of a small-cell, and a pool of BBUs (in a data center cloud) are run by high performance and digital signal processing (DSP) processors. With such a C-RAN, not only the data rate and power efficiency of wireless transmissions can be substantially increased in a much smaller cell size, spectral usage can also be improved by applying joint radio resource management and cooperative multipoint processing (CoMP) in the cloud.